Alkylation of naphthenes



Patented Dec. 5, 1939 UNITED STATES I PATENT OFFI E I 2,182,557 ALKVYLATION or. NAPHTHENES Aristid V. Grosse, Chicago, 111., assignor to Uni versal Oil Products Company, Chicago,'1ll., a

corporation of Delaware No Drawing. Application August a, 193': I Serial No. am

4 Claim.

The cyclopropane and cyclobutane necessary for the process may be produced by the action of sodium on dihalogen derivatives of propane and n-butane respectively in which halogen substitution is on-the end-carbon atoms. The reactions 01 this method of formation are shown in the following equations. v t

More specifically the invention is concemedwith catalytic processes which enable the production .of higher molecular weightderivatives of the more stable 6 carbon atom naphthenes by the addition of alkyl groups through the agency of the designated cycloparaflins.

The art of synthesizing organic compounds and particularly those of a hydrocarbon'character with which the present invention is concerned is important in view of the 'fact thatspecial hydrocarbons in any one series may have peculiar characteristics rendering them suitable for use either as a basis for the development of useful derivatives or direct use in hydrocarbon mixture's'such as, for example, those employed as fuels for internal combustion engines, lubricants, etc., and the present. invention is a contribution to the art of catalytically synthesizing such hydrocarbons.

In one specific embodiment theinvention comprises treatment of relatively stable and ordinarily unreactive naphthenes having 6 carbon atoms in the ring with cycloparafflns containing 3 and 4 carbon atoms in the ring and comprising cyclopropane and cyclobutane to form al'.-

kylated derivatives of the 6 carbon atom naphthenes while utilizing metal halide catalysts and particularly aluminum chloride, under relatively low temperature conditions.

The term naphthenes is herein used to designate polymethylene ring compounds-having 6 or more carbon atoms in the ring and which may or may not be substituted at various points by alkyl radicals. The simplest compound of this group is the compound designatedas hexamethylene or cyclohexane. .Naphthene hydrocarbons occur in practically all petroleums though in varying proportions depending upon the source of the crude oil and it is one of the featureslof the present invention that the naphthenic hydrocarbons present in petroleum distillates maybe alkylated by cyclopropane and/or cyclobutane to form higher molecular weight derivatives.

Compound BoilingJ point, specaltltig grcavity Cyclo ropane CycloEutane a. 11-12 0. 7038 Since the two cycloparafflnic compounds shownabove are gaseous at ordinary temperatures, the methods of operation whereby they are used to. alkylate the ordinary 6 carbon atom naphthenes are relatively simple and consist generally in passing cyclopropane or cyclobutane or a-mix ture of the two into the liquid naphthene hydrocarbons containing suspended therein finely divided anhydrous aluminum chloride or other catalytically reactive metal halides such as, for

tion of such catalysts requires the concurrent use of. a small proportion of a hydrogen halide such as hydrogen chloride, and this compound is preferably admitted to the reaction zone in admixture with the-cyclopropane or cyclobutane. Operations may beconducted according to the batch system in which the mixture of cycloparaflin and hydrogen halide is passed into a static body of -naphthenic hydrocarbon liquid example, zirconium chloride. The effective acuntil the desired degree of alkylaticn is effected or continuous systems may be employed in which the'cycloparaflin and hydrogen halide are injected into a moving stream oi liquid hydrocarbons containing suspended halide catalyst. After an alkylating operation the solid catalytic material is allowed to settle and the supernatant liquid decanted and subjected to fractional distillation for the recovery or individual compounds or selected fractions. The alkylated products may bewashed with caustic sodaor other alkalies to remove traceso! halogen acids or acid products of the reactions and the spent catalyst may be treated by any necessary method to restore it to the condition fitting it for further service. i

The present process is applicable to the treatment of either straight run or cracked gaslolineii v with 3 and 4 carbon atom cycloparaiiins since all such gasolines contain varying percentages oi. naphthenes as well as paraiiins and aromatics. the cracked gasolines containing in addition deiinite percentages of oleflns. In the treatment of gasolines with the reactive cycloparaiilns the principal reactions involve the addition of the propyl and the butyl radicals to the various hydroc'arbon components, the mechanism involving the opening of the 3 and 4 carbon atom cycloparafiln rings to furnish the propyl and butyl groups.

The temperatures of operation are preferably maintained at points below normal atmospheric temperature when using aluminum chloride and hydrogen chloride which is in general the preferred catalyst combination both on accountoi the availability and relative cheapness of these materials and their eflective action when used in proper proportions. Thus temperatures of approximately 40 to +10 C. are utilizable in the case of individual naphthene hydrocarbons or naphthene hydrocarbon mixtures which are liquid under these conditions. In the case of higher molecular weight compounds which may be normally solid, these may be treated at more elevated temperatures and in the presence of less active catalysts than aluminum chloride, such as. for example, the zirconium chloride already mentioned which usually functions better under these conditions.

The iollowing example is given to indicate the types 01' reactions involved in the process oi'the present invention although the numerical data is not presented with the intent of unduly limiting its scope.

Methyl cyclohexane was maintained at a temperature of approximately -10 C. and about 10% of its weight oi. finely divided anhydrous aluminum chloride was maintained in suspension by'mechanical stirring. To eiiect the manufacture of propyl derivatives, a mixture of dry hydrogen chloride and cyclopropane was introduced into the liquid at a slow rate corresponding to complete absorption of the cyclopropane until approximately the molecular equivalent had been introduced at which time the run was stopped and the liquid product washed and neutralized and subjected to analysis to determine its character. The principal reaction involved is shown in the appended equation since the product was amass? substantially all methyl propyl cyclohexane as. shown on the right-hand side of the equation.

The methyl propyl cyclohexane was obtained as a water-white, narrow boiling fraction. boiling from 166.5 to 168.5 C. at'745 mm., having an index of refraction,

n:,=1.43s3 at 2s.1 density,

. d:5=0.7897 mol. wt. 135; C=85. 24% and H=14'.-17%. The presence of the cyclohexane ring in this product was proved by dehydrogenati'ng at 250 C. with a The nature of the present process and'the character of the results obtainable by its application are evident from the preceding specification and single numerical example although neither section is intended to unduly limit its scope.

I claim as my invention:

1. A process for the production of alkyl derivatives of naphthene hydrocarbons having at least six carbon atoms in the ring which comprises reacting the naphthenehydrocarbon with a cycloparaiiin having less than 5 carbon atoms in the ring in the presence of a metal halide and a hydrogen halide.

2. A process for the production of alkyl derivatives of naphthene hydrocarbons having at least six carbon atoms in the ring which comprises reacting the naphthene hydrocarbon with a cycloparaflln having less than 5 carbon atoms in the ring in the presence oi! aluminum halide and hydrogen chloride at temperatures below +50 C.

3. A process for treating naphthene hydrocarbons having at least six carbon atoms in the ring to produce propyl derivatives thereof which comprises reacting the naphthene hydrocarbon with below +50 0.

. ARISTID v. Gnossn. 

